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Part transfer offset on lathe work offset?


Oct 11, 2023
Hello! I'm looking for recommendations on how to do part transfers and work off the sub spindle on a HAAS St20y mill turn. Is it possible to do it all using One work offset G54? Or would I need G55 for the sub once the swap happens? Also tips on how to program the sub movements, do I leave at home and make all it's movements -values or do I home it where it'll clamp on the part any tips on this would be appropriate!!
Apparently this is sub day. How I do it:

*Set your main oriented tools off the face of the main chuck.

*Set your sub oriented tools off the face of the sub chuck in its home position.

*Set radial tools off whichever chuck they will be used with.

*Use a G10L2P1 Zx.xx A-x.xx to set G54 to the face of the stock. So if you have 1" stick out you'll have Z1. Then when you go to pick off it's very simple.

*Use another G10 line to set G55 for how far the part sticks out of the sub. This will be negative, Z-x.xxx. Sometimes short tools won't reach when the sub is home, so I'll send it to -1 or -2 and then add that to the offset.

Caveat: I'm not nearly as knowledgeable as some guys on here, it's entirely possible there's smarter ways to do this.
I have all of my tools essentially zero'd to my main collet (chuck?) face.

I use G10 P0 X0 Z-1. to set Part Shift (or whatever it is called).
I doo this in the header of every program, and I never have to call a fixture offset anywhere else in the program, and it is always there when I run the job again.

The Z-1. in the above example sets your part 1" from the chuck surface.
Always negative on a Fanuc, IDK about a Haas.

I park my sub at a place that sets my bnack face of my part to a whole number. (Z13" example)
From there I just write my code as if Z13. was zero.

G0 X0 Z12.9
G1 Z13.25
G0 Z12.9
T0 X15.

I will agree that most of your turning tools will work one side only, but there are times when you will want one for a longer shaft. But live tools - well those can go anywhere!

I just feel more in control when I know that everything is on the same page.
There's no right or wrong, just what you git comfortable with is all.


Think Snow Eh!